1. Field of the Invention
Exemplary aspects of the present invention generally relate to a gear train assembly and an image forming apparatus including the gear train assembly.
2. Description of the Background Art
Conventionally, there is known a gear train assembly employed in, but not limited to, an image forming apparatus, such as a copier or a printer, in which a distance between tips of the gear teeth and a surface that receives lubricant (hereinafter “lubricant receiver”) is configured to be the same before and after the gear meshes with a mating gear. Such a gear train assembly is disclosed in JP-2006-345595-A, for example.
With reference to FIG. 1, a description is provided of a related art gear train assembly 160. FIG. 1 is a cross-sectional view of the related art gear train assembly 160 as viewed from along an axial shaft of the gear train assembly 160.
According to JP-2006-345595-A, the gear train assembly 160 includes a first gear 162, a second gear 164 that meshes with the first gear 162, and first and second lubricant receivers 166 and 168, respectively.
The first gear 162 rotates in a direction indicated by arrow F, that is, clockwise. Therefore, the first lubricant receiver 166 catches lubricant G before the first gear 162 meshes with the second gear 164, whereas the second lubricant receiver 168 catches the lubricant G after the first gear 162 meshes with the second gear 164.
According to the above-described related art technology, the lubricant G is applied to the first gear 162 and the second gear 164. Moreover, as indicated by arrow Y and arrow Z, a minimum distance between the first gear 162 and the first lubricant receiver 166 is substantially the same as the minimum distance between the first gear 162 and the second lubricant receiver 168.
As a result, with this configuration, the lubricant G accumulates on both the first lubricant receiver 166 as well as on the second lubricant receiver 168, thereby preventing the lubricant G from accumulating on only one surface. In other words, the lubricant G is dispersed substantially evenly over those surfaces that should be lubricated.
However, in order to accommodate increasing demand for high-speed and high-precision operation in an image forming apparatus, it is further desired that the gear train assembly employed in the image forming apparatus generate little vibration and noise while at the same time providing improved durability.
In view of the above, it is desired to evenly and thoroughly apply the lubricant G to the entire gear train and prevent the lubricant G applied to the gear surfaces from being scattered and exhausted.
It is to be noted that the minimum distance described above refers to the shortest distance between the tips of the teeth of the gear and the surface that catches the lubricant, that is, the lubricant receiver. When the lubricant receiver includes a protrusion, projection, or the like, the minimum distance then refers to the distance between the tips of the teeth of the gear and the tip of the protrusion, projection, or the like.